There are many types of solid antiperspirant sticks that are commercially available or otherwise known in the antiperspirant art. These products typically contain an astringent material, e.g. zirconium or aluminum salts or combinations thereof, solubilized or dispersed in a suitable liquid carrier, and the solution or dispersion contained within a solid matrix that gives the product a solid stick form.
These solid antiperspirant sticks are ideally designed to provide effective perspiration and odor control while also being cosmetically acceptable during and after application onto the underarm area of the skin. In this context, “cosmetically acceptable” means that the product glides on smoothly during application, is non-irritating, and results in little or no visible residue (e.g., low residue performance) after application to the skin.
It is well known in the art that once applied to the underarm area, an antiperspirant film must have a certain level of adhesion to the skin in order to be effective. It is further known that using non-volatile liquids are one way to promote good adhesive properties in antiperspirant products. See, for example, U.S. Pat. Nos. 4,183,911; 4,174,386; 6,406,684; 6,451,295; 6,352,688; and 6,383,476. It is also known in the art that high levels of non-volatile organic fluids inhibit antiperspirant efficacy by impeding release characteristics from the applied product matrix. See, for example, U.S. Pat. Nos. 6,352,688; 6,383,476. Not wishing to be limited by theory, we believe that the non-volatile liquids promote adhesion by plasticizing the dried film applied to the skin.
Thus, prior art suggests that the higher the level of non-volatile liquids the better adhesion of the antiperspirant film to the skin can be achieved. At the same time, it is known in the art that high levels of non-volatile organic components negatively affect the product efficacy.